Merchant discounts and shoppers' confidence in expedited shipping resulted in a 31% increase of online retail in the two weeks leading to Christmas, Internet market-researcher ComScore Networks reported Thursday.

Though the busiest online shopping days were Monday, Dec. 12, and Tuesday, Dec. 13, the sales momentum continued till Christmas, with nontravel E-retail sales for the entire pre-Christmas season rocketing by 25% to $18.1 billion as compared with 2004. ComScore says the shopping season began Nov 1.

Among the season's online shopping trends, according to ComScore:

* Shoppers spent $4.1 billion on computer hardware, including peripherals and PDAs, a 14% year-to-year increase.

* Apparel and accessories garnered $3 billion, a 37% hike.

* Consumer electronics rose 20% to $1.3 billion.

Among the fastest growing categories: sports and fitness products, up 49%, and sales of event tickets, a 37% increase. The buzz created by Microsoft's Xbox 360 and Sony's PlayStation Portable propelled a 34% jump in sales of video games, consoles, and accessories.

The marketing company also reports that online sales of gift certificates rose 19%.

Ebay and Amazon were the top two online retail sites, but seven of the top 10 Web stores were multi-channel retailers, led by Wal-Mart, Apple Computer, and Target.